Thousands of people are fleeing their homes and hospital patients are being flown to Brisbane on Tuesday as a tropical cyclone approaches the north Queensland coast in Australia.
Queensland Premier Anna Bligh said lives could be lost when Yasi, expected to be more devastating than Cyclone Larry in 2006, makes landfall between Cairns and Innisfail.
On Tuesday night the Category 3 storm was moving near the Solomon Islands, but disaster officials say they have not yet received any reports of damage.
Yasi blew across the northern islands of Vanuatu on Monday. There have been reports of flooding and officials expect significant damage to crops.
The cyclone is expected to intensify to a Category 4 system with winds of up to 250km/h before hitting the Queensland coast between Cairns and Innisfail about 1am AEST on Thursday.
Much of the coast is also braced for a dangerous storm surge - a threat that has already forced many to flee from low-lying homes.
Ms Bligh told a media conference on Tuesday the storm was tracking as more intense and "significantly larger" than Cyclone Larry, which devastated the region in 2006, the ABC reports.
Entire suburbs in some parts of the region will be evacuated, she said.
Deputy Police Commissioner Ian Stewart said mandatory evacuations orders are likely to be put in place for all affected areas.
Ms Bligh said the storm's eye could take more than an hour to pass and warned that the strongest winds would hit after the eye had passed.
Category 4 is the second most destructive storm in the five-category rating.
In January, floods in Queensland swamped thousands of homes and killed at least 35 people.